Introduction Letter

I'm writing intro letters to 2 attorneys that I was referred to. It's my first SERIOUS marketing start. I've been getting all sorts of things settled to get my business started up, but the fear of both success and failure has had me doing a lot of procrastinating, which ends NOW. Any good tips for introduction letters? I did the VMI home course and home apprenticeship, so basically going by the guidelines there. The letters WILL go in the mail tomorrow, just hoping for some last minute words of wisdom (or wisdom I can use on future letters). One is to a very experienced attorney, the other one is only a year out of law school, so my letters to both are very different. Experienced, trying to focus on how I can help him out even though I know he's already adept at the medical stuff but this way he can focus on the legal stuff. The new attorney, how I can help him screen his cases and I can handle medical, he can handle legal.
For the initial letter, I plan to include letter, business card and a brochure.
Any other tips? (Or words of encouragement? I'm starting to understand why tons of nurses take the classes but only a few actually end up doing the work. It's so much scarier to market yourself than to go apply for a job at a hospital with a hundred RN openings!)